Concrete staircase

A concrete solution to waste

Creating a building product from waste from aluminium production

Our scientists, working with leading sustainable construction materials company Lafarge Canada, have made a cement product using waste from aluminium smelting. We call it Alextra.

Because it’s made from waste, Alextra helps reduce landfill, uses fewer non-renewable resources, and helps our customers meet their sustainability goals too. Plus it’s cheaper than alternative materials.


aluminium producer in North America to create a safe material from used potlining


of the potlining waste from our aluminium operations in Quebec is treated to make it safe


of the potlining waste from our aluminium operations in Quebec is recycled


a year of cement made from Alextra

Alextra is made from used potlining – an essential part of the electrolysis process, where alumina is turned into aluminium. But for the process to work, potlining needs to be replaced every 5-8 years and the old lining contains hazardous materials, which need to be carefully managed.

Following years of work by our R&D team, in 2008 we set up a treatment plant in Quebec, Canada, that removes the hazardous substances from the used potlining and creates a safe material. We were the first aluminium producer in North America to do so. Today, all potlining waste from our Quebec-based aluminium operations is treated to make it safe, and around 80% is recycled into new products.

And now, through our partnership, Lafarge Canada will make around one million tonnes a year of cement using Alextra.

This is just one of the ways we are working to reduce waste. From 2021, we will also offer our aluminium customers in Canada and the US high-quality alloys made with recycled content, with a new service to recycle their aluminium scrap. And we are partnering with Anheuser-Busch InBev, the world’s largest brewer, to make beer cans from low-carbon and recycled aluminium.

Image: Dan Freeman